Screen detecting system of a wide screen television for detecting blank top and bottom areas
US5581304A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jan 17, 1996 |
| Grant date | Dec 3, 1996 |
| Priority date | — |
| Expiry date | Jan 17, 2016 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S348/913
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A screen detecting system of a wide screen television for detecting blank top and bottom areas of a video frame contained in conventional video signals and generating top and bottom display limits is disclosed. The top and bottom display limits are used by a display control system of the wide screen television to eliminate the blank top and bottom areas. The screen detecting system comprises a comparator for comparing the video signals with a blankness threshold, a sync circuit for separating vertical sync signals and horizontal sync signals from the video signals and generating a period signal after each horizontal sync signal, a blank period detector for detecting the output of the comparator within the time period of one period signal and generating a blank signal if no output is detected within said time period, and a display limit generator for generating the top display limit by checking the distribution of the blank signals after a first vertical sync signal and the bottom display limit by checking the distribution of the blank signals before a second vertical sync signal immediately after the first vertical sync signal.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.